Known display devices include, for example, one disclosed in Patent Literature 1. The display device according to Patent Literature 1 includes a rotation speed display panel to display the rotation speed of an internal combustion engine. The rotation speed display panel is circularly shaped and includes a numeric part and a graduation part which are formed on the outer peripheral side of the rotation speed display panel and extend in a circumferential direction of the rotation speed display panel. In the rotation speed display panel, a pointer turns pointing to the rotation speed of the internal combustion engine.
In a predetermined area of the graduation part, a red zone is formed as a predetermined zone to present a warning display representing a rotation speed range exceeding an upper-limit rotation speed of the internal combustion engine. The red zone is distinguished, for example, by color to be clearly discernable by a driver.
However, the red zone (predetermined zone) according to Patent Literature 1 is a belt-like design for merely displaying a rotation speed range exceeding an upper-limit rotation speed of the internal combustion engine. In recent years, demand has been rising for a new form of display by a display device.